ADS7953: Set to 12 channels. After several hours of operation, the values read back through SPI are all the values of channel 1

Set to 12 channels. After several hours of operation, the values read back through SPI are all the values of channel 1

The  external ad configuration is as follows

case 1:
st_ExtAdcCtlReg.all = 0x4200;
McbspbRegs.DXR1.all = st_ExtAdcCtlReg.all;
u16_ExADCFirstConfig=2;
break;
case 2:
st_ExtAdcCtlReg.all = 0x8000;
McbspbRegs.DXR1.all = st_ExtAdcCtlReg.all;
u16_ExADCFirstConfig=3;
break;
case 3:
st_ExtAdcCtlReg.all = 0x0FFF;
McbspbRegs.DXR1.all = st_ExtAdcCtlReg.all;
u16_ExADCFirstConfig=4;
break;
case 4:
st_ExtAdcCtlReg.all = 0x2C00;
McbspbRegs.DXR1.all = st_ExtAdcCtlReg.all;
u16_ExADCFirstConfig=5;
break;
case 5:
st_ExtAdcCtlReg.all = 0x2800;
McbspbRegs.DXR1.all = st_ExtAdcCtlReg.all;
u16_ExADCFirstConfig=6;
break;